This invention concerns refractory gunning apparatus and particularly such apparatus for gunning the inside of a furnace or ladle or the like.
Many types of apparatus for gunning refractory onto the interior of a furnace or ladle are known in this art.
For example, U.S. Pat. No. 3,351,289 discloses apparatus for applying a protective refractory coating to the lining of a basic oxygen furnace. The apparatus comprises a horizontal boom carrying a spray pipe with angled nozzle at the end. The boom and nozzle are inserted into the top opening of a BOF when such a furnace has been tilted on its side. It will be appreciated by those skilled in the art that this is not the operating position of the BOF, but a special position to which it must be moved for gunning. Also, although the nozzle can be rotated, it can only be rotated about a horizontal axis.
U.S. Pat. No. 3,737,489 discloses a method of applying refractory lining to hot metallurgical ladles, soaking pits, and furnaces using a device which is lowered vertically into the ladle through it open top, the device having a double-ended, horizontally disposed nozzle which rotates about a vertical axis.
Similarly, U.S. Pat. No. 4,167,246 shows apparatus for spraying a refractory lining, the apparatus having a plurality of nozzles shooting in a slightly downward horizontal direction and rotating about a vertical axis; the device is lowered vertically into the ladle.
Again, U.S. Pat. No. 4,270,949 discloses a coating lance which is lowered vertically into a BOF furnace and which has a plurality of downwardly angled nozzles which rotate about the vertical axis of the lance.
Finally, U.S. Pat. No. 4,541,971 shows a method of gunning refractories wherein a nozzle is lowered vertically into a vessel to be gunned through its open top, the nozzle being rotatable about the vertical axis of the supporting pipe and also about a horizontal axis through the lower end of the support pipe and at 90.degree. to the axis of the nozzle.
The apparatus of the present invention differs from those in the prior art in that it is designed to be used with a furnace, for example an electric furnace, in its operating position and to enter such furnace through the work door in its side wall. In other words, with the apparatus of the present invention, it is not necessary to remove the roof of an electric furnace (a substantial undertaking which results in loss of much heat from the furnace) to gun its interior. Also, the use of an overhead crane is not necessary with the apparatus of this invention.